I like to avoid smudging the renders head, I would suggest blurring the background a big and sharpening the focal a bit to create some depth. I' also work with your colors try adding gradient maps set on multiply, screen, or hue. and photo filters then play with the opacitys. A few other ways of getting good depth are using curves and exposure adjustment layers, and making a new layer > apply image> filter> other> High pass set use like 10% setting and then set the layer to overlay and then lower the layer's opacity.

I find with smudge tags if you throw in some spatter brushes with clip masking it tends to make it all come together. I only like to use smudging for like a background for clip masking and fractal/c4d effects.